1. Field of the Invention
The present invention generally relates to a surface configuration of a substrate-supporting device for a semiconductor-processing apparatus.
2. Description of the Related Art
In semiconductor manufacturing apparatuses, the susceptor plays the role of supporting the substrate. Accordingly, the susceptor surface is sometimes processed for the purposes of reducing foreign matters attaching to the back of the substrate, preventing the substrate from sticking, and so on.
As for the surface irregularity added to the susceptor by the aforementioned processing, the concaves do not contact the back of the substrate, while the convexes contact the back of the substrate and thereby support the substrate. This configuration has been shown to be very effective in reducing foreign matters attaching to the back of the substrate and preventing the substrate from sticking, as mentioned above. On the other hand, however, such configuration can cause the substrate to slide over the susceptor when the process conditions are changed while a film is being formed or during the cycle purge performed after a film has been formed. Transfer errors occurring when the substrate is transferred out after the film forming process, and non-uniform film thicknesses, have been reported due to this sliding.